Abuja: Nigerian Navy has sent a rescue ship to trace five Indians who were abducted by pirates from a German oil tanker off the coast of the country's notorious Niger Delta region.

"The Western Naval Command (WNC) under the leadership of the Flag Officer Commanding (FOC), Rear Admiral Ameen Ikioda was directed to send a rescue ship to the troubled vessel and ascertain if the ship was actually under arrest," Navy spokesman Commodore Kabiru Aliyu said.

He said the Navy will investigate the ship where it is at anchorage and if it is confirmed that the oil vessel was attacked, they will go after the pirates and rescue the kidnapped crew members.

Heavily armed pirates attacked and looted an oil vessel off the coast of Niger delta region on Monday, kidnapping five Indian sailors on board, the ship's operators, Medallion Marine said on Wednesday.

"The vessel (SP Brussels) was boarded by heavily armed pirates whist approximately 40 miles off the Niger Delta. The pirates ransacked the vessel for personal belongings and took five crew members with them on their departure." the operators said in an initial statement and later clarified that the five crew members were Indians.

Medallion Marine said they are working hand-in-hand with authorities here to get the abducted men released.

Piracy and oil theft is a regular phenomenon in Nigeria especially in the delta region where oil is produced. Similar attacks are also witnessed off southern commercial city of Lagos.

On September 4, pirates hijacked a ship, MT Abu Dhabi Star owned by a Singaporean firm off the shores of Nigeria with its 23 Indian sailors on board.

They were later released. A week before then, an oil vessel was seized by pirates, off the Coast of Togolese capital of Lome and released few days later near Nigeria with its 23 Russian crew members.